Power driven plastering trowels



Nov. 18, 1958 J. D. DRUMMOND 2,860,506

POWER DRIVEN PLASTERING TROWELS Filed July 26, 1954 'III'I'I'II INVENTOR JOHN D. DRUMMOND AT TORNEY United States Patent POWER DRIVEN PLASTERING TROWELS John 1). Drummond, North Burnaby, British Columbia,

. r Canada Application July 26, 1954, Serial No. 445,628

4 Claims. c1. 72-136) My invention relates to improvements in power driven plastering trowels;

The object of 'the invention is to provide a manually operated motor driven trowel capable of scratching ofi irregularities or excess particles from the initial or brown coat of plaster after initial setting has taken place, smoothing on the initial putty or key coat and if a secondary putty coat is applied, applying pressure thereto as required to take out scratches and level up the surface, working the semi-set material from high to low areas, and finally troweling off the surface to develop a close grained high gloss finished surface, if desired.

A further object is to apply water to the surface as and where required while the trowel is being moved over the surface.

An important object of the invention is to provide a device, which, when spreading plaster from one spot to another as in filling a slight depression from a slight projecting area, will so move the plaster inwardly from the periphery of the trowel that no curved ridges or other blemishes are left in the trail of the trowel.

Referring to the accompanying drawings:

Figure l is a front elevational view of the invention.

Figure 2 is a side elevational view.

Figure 3 is a sectional detail view of the rotating disk showing the mounting of a trowel blade thereon.

Fig. 4 is a plan view showing the water control to the trowel.

In the drawings like characters of reference indicate corresponding parts in each figure.

The numeral 1 indicates generally a pistol grip type motor having a driven shaft 2 fitted with a pinion 3. The motor is provided with a handle 5 from which a trigger 7 projects for controlling the motor. An elongated bearing 9 is mounted upon the motor housing and in this bearing a hollow spindle 10 is journalled. The spindle 10 is provided with a flange at its outer end as at 12 to support a disk or face plate 14. The hollow spindle is open at its flanged end to deliver water through the centre of the disk 14 onto the face of the work, and the inner end of the bearing 9 is fitted with a screw cap 16 which serves as a thrust bearing for the spindle and is connected with a tube 17 communicating with the bore of the spindle. A valve 19 is carried by the bearing 9 which communicates with the tube 17 and is adapted for connection to a water service hose 20.

As a convenience in handling the device, a handle 22 is mounted to project from the bearing 9, which will enable the operator to use both hands in manipulating the tool on a wall or ceiling surface.

The disk 14 is fitted on its rear face with a ring gear 24 which is engaged by the pinion 3 of the motor to rotate said disk at a relatively low speed compared with that of the motor. The disk 14 is provided with a plurality of equally spaced slots 25, each of which slots is provided along the leading edge of the slot with one or more clips 26 having fastening screws 27. The slots 25 are tangential to an imaginary circle radially spaced from the center of the disk. The clips are located at points spaced from the center of the disk and serve to hold in adjusted position a plurality of resilient blades 29 which may be of any desired material, such as steel, plastic, rubber or otherwise. The blades here shown have trailing edges 32, the trailing edges projecting substantially beyond the periphery of the disk or bladecarrying member and have a rounded outer or corner portion 33. The outer end of each trailing edge 32 and also its rounded outer portion 33 is disposed to lead the inner end of said trailing edge to a substantial degree when rotating in the normal direction, as shown by the arrow in Figure 1, so that any loose or un-set plaster engaged thereby will be urged inwardly towards the center of the disk and brought under the slope of the next following blades, thereby to be troweled into firm and smooth contact with the surface. The leading edge 34 of each blade is at an acute angle to the trailing edge 32 so as to aiforda greater resilience to the blade at its rounded corner portion33, so that when it is desired to wipe plaster from a high spot into a lower spot greater pressure may be applied by tilting the device to said corner portion of the blades as they traverse said high spot to create a spreading action thereunder and to leave the inner portion of the trailing edges to effect a smoothing and compacting action on the material so moved inwardly.

In use on scratch coat work to substantially straighten up the work the blades are removed from the disk and an abrasive material attached thereto, which serves, as the trowel is moved across the face of the work, to scratch oif unwanted materials. When a putty coat has been applied to the base or brown coat of plaster and initial setting has taken place, the device is again used with the resilient blades 29 fitted to the disk as above described. The rotating blades smooth out and compact the putty or other finishing coat, filling in low spots and small depressions in the surface. Water is applied to the work through the center of the disk 14 by manipulating the valve 19 as required so as to keep the material moved by the blades in a suitably plastic condition. The constant rotation of the blades as the device is moved transversely of the work produces a finish which is entirely free from trowel marks, pin holes or other defects and may be brought to a substantial gloss or otherwise dependent on the extent of the troweling. The trailing edges being disposed at a tangent to an imaginary circle radially spaced from the center of the disk and being of substantial length and closely spaced one from another by virtue of the overlapping arrangement of the blades ensures that a maximum area of the blade is utilized to obtain the desired troweling effect.

What I claim as my invention is:

1. A power-driven trowel, comprising a motor having a housing and a handle therefor, a blade-carrying member rotatably mounted in said housing and connected to said motor so as to be driven' thereby, a plurality of blades secured to said blade-carrying member at points spaced from the center of said blade-carrying member and having trailing edges tangential to an imaginary circle radially spaced from said center, said blades extending at an inclination outwardly from said member for for engagement with plaster material, and means for discharging Water onto said material through the central portion of said blade-carrying member, whereby the outer portion of the trailing edge of each blade, by leading the inner portion thereof in rotation, directs the material inwardly to mix with said water during movement of the trowel to keep said plaster material plastic.

2. A power-driven trowel, comprising a handle-equipped housing, a motor therein, a blade-carrying member rotatably mounted in said housing and connected for driving movement by said motor, a plurality of blades in overlapping relation secured to said blade-carrying member and at points spaced from the center of said bladecarrying member, said blades having trailing edges tangential to an imaginary circle radially spaced from said center, said blades extending at an inclination outwardly from said member, whereby the outer portion of the trailing edges of said blades lead the inner portions thereof to direct material inwardly, and means for discharging water through the central portion of said bladecarrying member 'for coaction with the plaster material moved inwardly by said blades.

'3. The structure of claim -2, in which said overlaplapping blades have outer tip portions which are not in overlapping relation and which are tapered to increase the resilience thereof.

4. A manually-operated power-driven trowel, comprising a motor housing equipped with a handle, a motor in said housing and equipped with a drive shaft, a rotatably-mounted disk connected to said motor shaft so as to be driven thereby, said disk being centrally apertured, a valve-controlled conduit communicating with said aperture in the disk for discharging water therethrough, a

plurality of blades secured to said disk at points radially spaced from said disk aperture, each of said blades having a trailing edge tangential to an imaginary circle radially spaced from said disk aperture, said blades extending outwardly at an inclination from the disk, the outer edge portion of each trailing edge leading the inner portion thereof so as to direct plaster material engaged thereby inwardly, said blades having overlapping inner portions spaced from said aperture so as to permit the discharge of water therethrough into the area between said blades, whereby the action of said blades confines the discharged water in the area in which the blades are in contact with the plaster.

References Cited in the file of this patent UNITED STATES PATENTS 2,181,375 Leistner et a1. Nov. 28, 1939 2,561,521 Lent July 24, 1951 2,605,683 Boulton Aug. 5, 1952 2,616,285 Shields Nov. 4, 1952 FOREIGN PATENTS 113,320 Australia June 13, 1941 

